Off-spinner Charli Knott demolished Surrey with figures of four for 15 to eliminate the defending champions on home soil and send The Blaze into the Vitality Blast final.
Knott, whose performance lifted her to the top of the tournament’s wicket-taking charts on 25, was backed up by fellow spinner Josie Groves (two for 18) and seamer Grace Ballinger (three for 18).
The Blaze were thoroughly efficient in the field at the Kia Oval as Surrey were rolled for a paltry 105 in just 15.2 overs – and they made short work of the target, with Kathryn Bryce (34 from 34) top-scoring to seal victory with 21 balls to spare.
The resounding win secured a place for the 2024 T20 champions in this year’s showpiece game, against either Hampshire or Durham.
Having won the toss, The Blaze gained early successes when Ballinger sent down a slower-ball yorker to castle Danni Wyatt-Hodge for a duck, then had Kira Chathli caught attempting to ramp her.
The hard-hitting Laura Harris injected some momentum, thumping three boundaries off Charley Phillips to reach 18 from seven balls – only to be tempted by a floater from Knott that she drilled straight to cover.
Surrey skipper Bryony Smith (29 from 28) did her best to hold the innings together but, once she top-edged Knott to mid-off in the 10th over, the spinners tightened their grip ever more firmly.
Groves struck twice in quick succession to dismiss Alice Davidson-Richards (20 from 17) and Kalea Moore and, although Surrey did manage to clamber above three figures, Ballinger and Knott mopped up the tail in ruthless fashion, with 28 balls unused.
Faced with little pressure, there was no need for Tammy Beaumont and Sarah Bryce to take risks at the start of the chase and the pair added 38 in the powerplay before Bryce (16 from 15) missed a straight one from Moore.
Having begun slowly, Beaumont (29 from 30) soon found her rhythm after clipping Ryana MacDonald-Gay through midwicket for four and looked on course to steer her side home until she holed out chasing a wider delivery from Tilly Corteen-Coleman (two for 25).
Surrey should also have removed Kathryn Bryce, put down at point reverse-sweeping Dani Gregory, but it would almost certainly have made no difference to the outcome as The Blaze sealed victory in the 17th over.
Knott (21 from 18) cut and drove to the boundary with authority, while Bryce slammed successive fours off Moore but both perished with the scores level, leaving it to Emma Jones to sweep the winning run.
For more information about Rothesay, please visit www.ecb.co.uk/about/who-we-are/our-partners/rothesay